The pyrimidine compound with which the present invention is concerned has the following structural formula ##STR1## and is known as buspirone. The hydrochloride salt has been referred to in the prior art as MJ 9022-1 and as buspirone hydrochloride. Other acid addition salts thereof are named by combining "buspirone" with the appropriate word to define the acid from which it is prepared as in "buspirone hydrochloride". The latter is the United Stated Adopted Name (USAN); refer to J. American Med. Assoc. 225, 520 (1973).
The synthesis of the compound and the disclosure of its psychotropic properties are described in the following patents and publications.
1. Y. H. Wu, et al., J. Med. Chem., 15, 477 (1972).
2. Y. H. Wu, et al., U.S. Pat. No. 3,717,634 which issued Feb. 20, 1973.
3. L. E. Allen, et al., Arzneim. Forsch., 24, No. 6, 917-922 (1974).
4. G. L. Sathananthan, et al., Current Therapeutic Research, 18/5, 701-705 (1975).
5. Y. H. Wu, et al., U.S. Pat. No. 3,976,776, issued Aug. 24, 1976.
The use of buspirone hydrochloride as a novel anti-anxiety agent for the treatment of neurotic patients is described in G. P. Casten, et al., U.S. Pat. No. 4,182,763, issued Jan. 9, 1980. Currently, a New Drug Application (NDA) is pending before the U.S. Food & Drug Administration for the use of buspirone in the treatment of anxiety neurosis.
Buspirone has also been disclosed as being useful in alleviation of of extrapyramidal motor disorders in U.S. Pat. No. 4,438,119, which was issued Mar. 20, 1984, to Allen, et al.
Currently, other clinical studies are being conducted to provide support for the use of buspirone in panic disorders. This use of buspirone was disclosed in U.S. Ser. No. 791,182, which is presently pending.
The present invention can be distinguished from the above prior art in that it is directed to a patient population which is characterized by a disease state different from that related to general anxiety disorder, panic disorder, or extrapyramidal motor disorders. Descriptions of these three different disease states may be found in the text of the above-cited references. While patients may suffer from sexual dysfunction concurrent with one of the above anxiety or movement disorders, nonetheless, these are clearly different disease states. To indicate the magnitude of the problem of sexual dysfunction, it has been estimated that a disturbance of sexual functions affects 34% of medical out-patients above the age of 35 (cf: Slag, et al., "Impotence in Medical Clinical Outpatients", JAMA, 249 (13): 1736-1740 (1983)).
While it is recognized that psychiatric disorders such as depression, alcoholism, neuroses and psychoses can interfere with sexual functions; most psychotropic agents further impair erectile and orgasmic ability (cf: Story, "Sexual Dysfunction Resulting From Drug Side Effects", J. Sex Research, 10(2): 132-149 (1974); Mitchell, et al., "Antipsychotic Drug Therapy and Sexual Dysfunction in Man", Am. J. Psychiatry, 139(5): 633-637 (1982)).
A report disclosing the use of mesoridazine, a phenothiazine antipsychotic agent, in treatment of male sexual ##STR2## function appeared in 1968 in the Czechoslovakian journal, Act. Nerv. Super, 10/3, pages 261-262. Mesoridazine, which is not structurally related to buspirone, is highly sedating and seemed mainly to affect premature ejaculation.
In summary, there exists nothing in the prior art which would teach or suggest that buspirone and its pharmaceutically acceptable salts would be useful in treatment of sexual dysfunction in both sexes.